Bethesda, MD, August 19, 2008 – The prevalence of obesity and overweight in the United States coupled by the increased risk of gastrointestinal diseases related to obesity raises serious implications for the health of Americans. Several scientific studies in the August issue of The American Journal of Gastroenterology examine the association between obesity and the risk of colorectal cancer and gastroesophageal reflux disease, or GERD.
Dr. Frank K. Friedenberg and colleagues from Temple University School of Medicine in Philadelphia provide an extensive overview of scientific research on the epidemiologic and pathophysiologic associations between obesity and GERD.
Several studies featured in the article highlight the correlation between increasing body mass index (BMI) and the frequency and severity of acid reflux symptoms. One particular study found that accumulation of abdominal fat, as measured by the waist-to-hip ratio, may be the most important risk factor for the development of acid reflux and related complications such as Barrett's esophagus and esophageal adenocarcinoma.
The authors also examined data on the effects of weight loss through diet or surgical methods on acid reflux disease. Several studies suggest weight loss through caloric restriction was beneficial in reducing GERD symptoms. When the authors compared the different surgical approaches for weight loss, a surgical technique called "Roux-en-Y" gastric bypass appeared to be the best method, and was most consistently associated with improvement in the symptoms and findings of GERD. "The mechanism of action through which this surgery is successful at improving GERD may be independent of weight loss and needs further examination," said Dr. Friedenberg.
High Body Mass Index Increases Risk of Colorectal Adenomas
Researchers at the University of Tokyo and Kameda General Hospital in Japan examined the effect of body weight on the incidence of colorectal adenoma in 7,963 Japanese patients who underwent colonoscopy between 1991 and 2003. Patients who had a family history of colorectal cancer, colorectal polyps, inflammatory bowel disease, colorectal surgery or who took NSAIDS were excluded from the study.
In this cross-sectional study, patients were classified into four groups according to their body mass index (BMI). Researchers found 20.7 percent of patients had at least one colorectal adenoma. Importantly, as the BMI increased, so did the prevalence of colorectal adenomas.
In a separate cohort analysis, 2,568 patients from the initial study underwent a second colonoscopy after one year to compare the effect of body weight changes on the development of new colorectal adenomas. The incidence rates of colorectal adenoma were 9.3 percent in patients who lost 5 percent or more in body weight; 16.2 percent in patients who gained 5 percent or more in body weight; and 17.1 percent in patients who neither gained nor lost weight.
Weight loss was associated with lowered incidence of adenoma, independent of gender, age, initial colonoscopic findings, and initial BMI. Based on their findings, the authors suggest that controlling body weight may decrease the risk of developing colorectal adenomas.
According to ACG President Amy E. Foxx-Orenstein, D.O., FACG, "The magnitude of the obesity epidemic adds a staggering burden to our current health care system. These studies point to the serious potential risks of GI disease for individuals who are overweight or obese."
Full text of the BMI and colorectal adenoma study is available on the ACG web site at http://www.acg.gi.org/media/releases/AMJGastrobodyweight.pdf
Full text of the GERD and obesity article is available on the ACG web site at http://www.acg.gi.org/media/releases/AMJGastro-GERDandobesity.pdf
About The American Journal of Gastroenterology (http://www.amjgastro.com)
Published monthly since 1934, the Journal is the College's official peer-reviewed journal. The goal of the Journal is to publish scientific papers relevant to the practice of clinical gastroenterology. It features original research, review articles and consensus papers related to new drugs and therapeutic modalities. The ACG Editorial Board encourages submission of original manuscripts, review articles and letters to the editor from members and non-members.
About the American College of Gastroenterology
Founded in 1932, the American College of Gastroenterology (ACG) is an organization with an international membership of more than 10,000 individuals from 80 countries. The College is committed to serving the clinically oriented digestive disease specialist through its emphasis on scholarly practice, teaching and research. The mission of the College is to serve the evolving needs of physicians in the delivery of high quality, scientifically sound, humanistic, ethical, and cost-effective health care to gastroenterology patients.
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